User input devices used for interfacing with an electronic data processing system or computing device take many forms including keyboards, mice, track balls, etc. Of particular interest in this disclosure are the various x-y input devices, commonly known as tablets, digitizing tablets or pen tablets. These tablets, which may be activated by touch, proximity or other such means using a finger, a stylus or even a mouse, are used to control the position and movement of a cursor on the display of a computing device, and for communicating and implementing various software and system commands, functions and features.
In general, a penlike pointing device is used with the tablet to provide pen-like control of the onscreen cursor. Such pointing devices also provide the same features and functions of a mouse by using either buttons on the pointing device itself, or by ‘clicking’ the pointing device tip on the tablet (e.g. tip contact with a proximity-activated tablet or tip tapping with a touch activated tablet reproduces ‘clicking’ functions of a mouse). Furthermore, the boundaries of the active surface of the tablet generally correspond to the boundaries of the display such that the user may instinctively position the cursor on the display using the tablet boundaries as reference. Uses for these devices include for example point-and-click functions common with a mouse, drawing and image modification functions in various software, signature digitization, as well as other functions where the use of a pen-like object for interfacing with a computing device is beneficial or preferential over the use of a standard mouse and/or keyboard.
One particular drawback of these devices is that the user of a tablet must focus on the display screen of the computing device while somewhat blindly manoeuvring the stylus or pointing device on the tablet at its side. Unlike using a pen on a piece of paper, the eyes of a tablet user are focused on the display screen and away from the physical “pen and paper”, thereby reducing user dexterity and proficiency. Furthermore, as the user lifts his/her hand and pointing device from the tablet, the cursor can no longer be controlled by the pointing device until the pointing device is returned to the tablet, or close thereto. Lateral displacement of the hand and pointing device at a vertical distance from the tablet exceeding a certain tablet sensitivity threshold can thus not be followed and visualized on the screen.
The present invention, described herein and with reference to the appended illustrative drawings, provides a camera assisted tablet, and alternative embodiments thereof, that overcome the above and other drawbacks of prior art systems.